Reliability of the Spanish version of the Nottingham health profile in patients with stable end-stage renal disease

Objective: Since reproductibility of results is a basic prerequisite of health status measures for its use in prospective and evaluative studies, the reliability of the Spanish version of the Nottingham Health Profile (NHP), a multi-dimensional perceived health status measure, was assessed in a sample of stable end-stage renal disease (ESRD) patients. Methods: The NHP was administered on two occasions four weeks apart to a group of hospital hemodialysis program patients who were clinically stable according to their physicians. Correlations of scores and agreement of first and second administrations were assessed together with internal consistency. Afterwards, analyses were repeated taking into account the time (before, during or after the dialysis) and the method of administration (self vs interviewer), and the interviewer. Results: Spearman correlation coefficients (rs) between responses to the first and to the second administration were > 0.6 for all of the six dimensions of the NHP (range=0.69-0.85) and in every sub-group analyzed (P 0.4 (0.48-0.65). Internal consistency was 0.91 for the whole profile and > 0.5 (0.58-0.86) when analyzed by individual dimensions. Reliability did not vary significantly with the time nor the method of administration (self or interviewer). Conclusions: Overall, results suggest that the Spanish version of NHP is sufficiently reliable to be used in ESRD patients. While a higher reliability would have been achieved by a shorter retest period, the study provides a realistic approximation to the reliability of the questionnaire in actual research and clinical applications.